A head-up display, or HUD, is generally installed on the dashboard of a vehicle and is configured to provide the vehicle operator with information such as the speed of the vehicle or the route to follow by superimposing them on the external environment between the vehicle windshield and the driver. Thus, the driver can maintain all his or her attention while he/she monitors at the same time the information or data of the vehicle and his external environment through the windshield. There are also head-up displays installed in the cockpits of aircraft in the pilot's field of vision, whose process is the same or similar to that of the automobile.
A head-up display generally comprises a combiner, a projector system capable of generating information to be viewed and a housing that can be secured on or integrated into the dashboard of the vehicle. The projector system, which is frequently installed in the housing that receives the combiner, and sometimes outside the housing, includes a projector, that is to say a light source, capable of producing a light beam representative of the information or data to be viewed and associated optics for guiding the light beam to the combiner. The combiner, which consists of a transparent plate or transparent mirror, forms a transparent display screen capable of displaying the information carried by the light beam emitted by the projector.
In addition, in order to protect the combiner from dust or other foreign elements when not in use, the combiner is mounted retractably, generally by pivoting or tilting, in a compartment open to the outside provided in the housing. For this purpose, the combiner is mounted on a mobile support, guided and driven to pivot and/or tilt by means of a drive mechanism actuated by an electric motor, from a retracted or non-use position in the compartment, to a deployed or in-use position outside the compartment and the housing.
U.S. Pat. No. 7,978,414 discloses a head-up display device for a vehicle, said device comprising a housing receiving a pivoting combiner in a housing, said combiner being formed by a substantially flat glass or polymer substrate and being mounted on a support by clamping or blocking its base, that is to say of one of its sides. When mounted, the combiner presents a side facing the driver and an opposite side facing the windshield of the vehicle. The support consists of two walls or parts, namely a wall, called the front wall, and a wall, called the rear wall, each shaped with a profile corresponding to the profile of the combiner, and having a plane or slightly concave profile so as to follow the outline of the side or base arranged between the two walls. It further includes a projector, positioned above or below the combiner for projecting information on the combiner, and a positioning mechanism for pivoting and driving the combiner from a horizontally extending retracted or stored position inside the compartment, to a vertically extending deployed or in-use position for the purpose of displaying and viewing the data. The front wall is placed against the front face of the combiner and the rear wall is placed against the rear face of the combiner. Clamping or blocking the combiner in the support, particularly between the two walls, prevents the combiner from being bent or deformed or subjected to any other physical distortion during the periods when the combiner and the positioning mechanism are exposed to extreme high or low temperatures during use or storage. The two walls are fixed to the combiner by fastening means such as threaded elements, for example screws, or by gluing the walls and the combiner. The screws are engaged through the walls and the base of the combiner. The screw heads are on the side of the front wall and are screwed into threaded holes provided in the rear wall.
However, in a head-up display such as the one disclosed in the aforementioned U.S. Pat. No. 7,978,414, in the deployed or in-use position of the combiner, dust or other foreign elements penetrate the housing through gaps or openings between the latter and the combiner or the support and thus reach the mechanical and optical elements, negatively affecting their operation and/or requiring costly and difficult cleaning tasks. In addition, the screws, more particularly the heads of the screws, are visible in the in-use position of the combiner, which negatively affects the aesthetics of the device.
US Pat. No. 2014/012085 relates to a head-up display for a vehicle, said display comprising a semi-transparent mirror (combiner), pivotally movable, to display driving assistance information such as the speed of the vehicle or navigation data, a sending part (projector system) for sending and transmitting the information to the mirror, a motor for transmitting the rotational force to the mirror to move it in the open position (use or deployment) or closed position (retracted or stored). In the closed position, the mirror closes the opening of a compartment provided in a housing integrated in the upper part of the instrument panel of the vehicle or attached to said panel. The mirror is supported by a pivoting axle mechanically connected to the motor to receive the rotational force for pivoting the mirror, which is integral therewith, between its two, open and closed, positions. On the other hand, such a head-up display, in its implementation in a vehicle marketed under the name “Mazda 3 S” (https://www.youtube.com/watch?v=4SR6zNsjAPE), includes a fixed cover extending horizontally in the compartment of the housing. Such a fixed cover is adapted and intended to hide at least a portion of the mechanical and/or optical parts located in the compartment and is stationary relative to the combiner or to the axis or support of the pivoting combiner. The implementation of a display of this type can also be viewed on the following website: https://www.youtube.com/watch?v=e9xvI7keQIM.
However, in a head-up display of the type disclosed in US Pat. No. 2014/012085, in the deployed or in-use position of the combiner, dust or other foreign elements penetrate into the compartment through gaps or openings located between the combiner and the edge of the opening of the compartment or the fixed cover and thus reach the mechanical and optical elements, negatively affecting their operation and/or requiring costly and difficult cleaning tasks.